Model 408 NO Calibration Source Manual Rev. D-3
15
Table 5.1. Troubleshooting the NO Calibration Source
for performance
problems.
Problem/symptom
Likely cause
Corrective action
Instrument does not turn
on.
Power not connected
properly or circuit breaker
open.
Power cable not connected
to circuit board.
Check external power
connection for reverse
polarity or a short and wait
a few minutes for the
thermal circuit breaker to
reset.
Remove top cover and
disconnect and reconnect
power cable to circuit
board.
Instrument turns on then
powers off.
Burned out air pump.
Remove top cover and
unplug air pump. Turn
instrument on; if it remains
running, then the air pump
motor is burned out and
shorting. Replace air
pump.
Display is blank or
nonsense.
Bad connection of display
to circuit board.
Remove top cover and
reconnect display to circuit
board. Check solder
connections to display.
Target temperature is
never reached.
Absent or loose connection
of temperature probe cable
to circuit board.
Heater is burned out
Remove top cover and
reattach connector to
circuit board.
Replace cartridge heater.
Instrument does not
output NO.
Photolysis lamp is burned
out.
Cable not properly
connected between lamp
and circuit board.
Replace lamp and
recalibrate instrument.
Remove top cover and
reconnect lamp cable to
circuit board.
Select Switch does not
work.
Cable not properly
connected between Select
Switch and circuit board.
Remove top cover and
reconnect Select Switch
cable to circuit board.
Serial port does not
work.
Cable not properly
connected between serial
Remove top cover and
reconnect serial port cable
